EP0642855B1 - Casting mold - Google Patents
Casting mold Download PDFInfo
- Publication number
- EP0642855B1 EP0642855B1 EP94113405A EP94113405A EP0642855B1 EP 0642855 B1 EP0642855 B1 EP 0642855B1 EP 94113405 A EP94113405 A EP 94113405A EP 94113405 A EP94113405 A EP 94113405A EP 0642855 B1 EP0642855 B1 EP 0642855B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- core
- molten metal
- cast
- casting
- weight
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/10—Cores; Manufacture or installation of cores
- B22C9/101—Permanent cores
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
- B22D15/02—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of cylinders, pistons, bearing shells or like thin-walled objects
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/20—Accessories: Details
- B22D17/22—Dies; Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies
- B22D17/24—Accessories for locating and holding cores or inserts
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D19/00—Casting in, on, or around objects which form part of the product
- B22D19/0009—Cylinders, pistons
Definitions
- the present invention relates to a method used to produce a cast product having a concave portion, e.g., a hole or the like, therein.
- a core or a core pin has been used conventionally when producing a cast product which has a concave portion such as a hole or the like therein.
- the core or the core pin is subjected to a holding force which results from the shrinkage of a molten metal during solidification. Accordingly, it is difficult to remove the core or the core pin from the resulting cast product after cooling the cast product.
- it is usually tapered gradually from wide to narrow in the direction toward its leading end.
- the cast products When the cast products are produced by using the core or the core pin, they come to have a concave portion such as a hole or the like.
- the resulting concave portion is inevitably formed in a tapered hole whose inside diameter reduces from large to small in the direction toward its inner side.
- it is hard to make the resulting concave portion which has an identical inside diameter over its entire length.
- it is a routine practice to carry out machining on the inner periphery of the concave portion after the casting, thereby establishing an identical inside diameter over the entire length of the concave portion.
- the molten aluminum or zinc is solidified rapidly at its surface where it is brought into contact with a mold. Consequently, at the surface where the molten aluminum or zinc is brought into contact with the mold, there is formed a healthy layer in which no bubbles are involved in a thickness of from about 0.7 to 1.0 mm.
- blow holes in the deeper layer disposed under the healthy layer because the molten aluminum or zinc is solidified at a slower rate in the deeper layer.
- the machining allowance should be enlarged on the inner side of the concave portion so that it goes beyond the healthy layer.
- the blow holes come to be exposed to produce defects.
- the concave portion should be machined in excess of about 3.49 mm at its innermost portion. Accordingly, the concave portion is machined completely beyond the healthy layer.
- a casting process using a cast insert member has been known, in which casting is carried out after a cast insert member e.g., a liner or the like, formed independently is disposed in a cavity.
- a cast insert member e.g., a liner or the like
- casting is carried out after disposing a protective member in a cast insert member. If such is the case, there should be provided a clearance between the cast insert member and the protective member. Consequently, it is difficult to completely get rid of the deformation in the cast insert member.
- the protective member in order to prevent the protective member from being stuck in the cast insert member due to the deformation in the cast insert member, the protective member should be formed in a configuration having a draft taper. Consequently, when the cast insert member is deformed to conform to the configuration of the protective member, it is required to machine the inner periphery of the cast insert member after casting, and at the same time, there occur problems in that the machining has resulted in the partially fluctuating thickness in the cast insert member. Furthermore, there are produced defects which result from the molten metal invasion into the clearance between the cast insert member and the protective member.
- DE-C-973984 discloses a casting core made of light metal and having a coefficient of expansion which is larger than the amount of shrinkage of a molten material. While cooling, the solidifying alloy shrinks less than the core. Thus, the core can easily be detached from the cast product.
- the core is of light metal, it can be provided with an oxide film on its outer periphery or cooled by means of a liquid which is leaded through a bore within the core.
- the oxide film or the liquid cooling are only used to prohibit the core from melting. Therefore, the cooling of the core is used to hold the temperature of the core some less the melting point of the core-material. Thus, the temperature of the core while solidifying of the cast product is nearly the same as the temperature of the cast product.
- JP -A- 63144845 a similar casting method is known.
- This method also uses a core having a thermal expansion coefficient which is greater than that of the casting material.
- the core is preheated to a prescribed temperature which is adapted -on the one hand- to the average temperatures of the components when solidification starts, and -on the other hand- to the difference in the thermal expansion coefficients.
- the present invention is developed in view of the aforementioned circumstances. It is therefore an object of the present invention to provide a method for producing a cast product with a concave portion which still allows to give the concave portion an inside diameter as identical as possible over its entire length and to reduce a machining allowance after casting, and which leads reliably to a large enough clearance between the core and the cast product, even with a broad range of cast materials.
- the core further includes a casting insert member disposed around its outer periphery.
- the core greatly expands thermally during casting. While it keeps the expanded state, the molten metal starts solidifying. Accordingly, the molten metal is subjected to a pressing force resulting from the expansion of the core during its solidification process. With the present casting mold, it is possible to inhibit the defects like the shrinkage cavities and so on from producing in the resulting cast products.
- the core shrinks more than the molten metal adjacent thereto does. Consequently, there arises a clearance between the outer peripheral surface of the core and the inner peripheral surface of the concave portion formed by the core in the resulting casting products. As a result, even when the untapered configuration is given to the core, it is possible to remove the core from the concave portion with ease and to reduce the machining allowance in the concave portion which has been usually required after casting.
- the core includes the cast insert member disposed on its outer periphery as done in the preferred form of the present casting mold
- casting is carried out while the core is fitted into the cast insert member.
- the core expands greatly, thereby outwardly pressing the inner peripheral surface of the cast insert member.
- it is possible to reduce the clearance between the cast insert member and the core to zero.
- it is possible to inhibit the cast insert member from being deformed by the shrinkage stress of the molten metal and to prohibit the molten metal from invading between the cast insert member and the core.
- the core shrinks considerably to thereby produce a clearance between itself and the cast insert member. Consequently, it is possible to remove the core from the cast insert member with ease. Therefore, it is unnecessary to give the conventional tapered configuration to the core. Thus, it is possible to get rid of the step of machining the cast insert member after casting.
- the cast insert member is inhibited from being deformed by the shrinkage force of the molten metal. Accordingly, it is possible to get rid of the step of machining the cast insert member after the casting and to prevent the strength of the cast insert member from being deteriorated.
- FIG. 1 there is illustrated a schematic cross-sectional view of a casting mold of a First Preferred Embodiment according to the present invention.
- the casting mold comprises a pair of main molds 1, 2, a cavity 10 formed by the main molds 1, 2, and a cylindrical slider pin 3 disposed in the cavity 10.
- the casting mold is used for casting an aluminum die-cast component part.
- the slider pin 3 is formed of a high-manganese-content alloy which includes Mn in an amount of 22% by weight.
- Casting was carried out by charging a molten aluminum alloy into the casting mold constructed as described above.
- Figure 2 there are illustrated a variation of the temperature of the molten aluminum alloy (or a cast product) with the time elapsed and a variation of the temperature of the slider pin 3 therewith.
- the temperature of the molten aluminum alloy decreased gradually, but the temperature of the slider pin 3 increased sharply so as to approach the temperature of the molten aluminum alloy. Since the slider pin 3 exhibited a thermal expansion coefficient greater than that of the molten aluminum alloy, the slider pin 3 expanded to apply a pressing force to the molten aluminum alloy.
- FIG 4 there is illustrated a casting mold which has been used conventionally.
- a slider pin 3' was employed which had a maximum diameter of 30 mm. Since it was formed of a steel, it exhibited a thermal expansion coefficient smaller than that of the molten aluminum alloy.
- the slider pin 3' was provided with a draft angle of 1 degree in order to make it likely to be removed from the cast product.
- the slider pin 3 could be removed from the cast product with ease even when it had a maximum diameter of 30 mm and it was provided with a draft angle of 15 minutes. If such was the case, it was necessary to machine the inner periphery of the hole portion only by a machining allowance of 0.8 mm at maximum after the casting. Therefore, it was possible to inhibit the material from being wasted, and at the same time there was produced no defect resulting from the shrinkage cavities.
- the slider pin 3 for casting an aluminum die-cast component part can be made from either a high-manganese-content alloy which includes Mn in an amount of from 10 to 25% by weight, C in an amount of from 0.2 to 1.5% by weight, Cr in an amount of from 1 to 3% by weight, and the balance of Fe and inevitable impurities, an austenite stainless steel, or a bimetallic alloy which includes Mn in an amount of from 65 to 80% by weight, Cr in an amount of from 10 to 20% by weight, and the balance of Ni and inevitable impurities.
- a high-manganese-content alloy which includes Mn in an amount of from 10 to 25% by weight, C in an amount of from 0.2 to 1.5% by weight, Cr in an amount of from 1 to 3% by weight, and the balance of Fe and inevitable impurities
- an austenite stainless steel or a bimetallic alloy which includes Mn in an amount of from 65 to 80% by weight, Cr in an amount of from 10 to 20% by weight, and the balance of Ni and inevitable impur
- FIG 3 there is illustrated a schematic cross-sectional view of a casting mold of a Second Preferred Embodiment according to the present invention.
- the casting mold is designed to cast an automotive engine block, one of the aluminum die-cast component parts. It comprises an upper mold 40, a lower mold 41, and a pair of slider cores 42, 42. Between the upper mold 40 and the lower mold 41, there is disposed a liner 5 (i.e., the cast insert member) for constituting an inner peripheral surface of a bore. Moreover, a core 6 is held by the upper mold 40 at one of the opposite ends, and it is fitted into the liner 5.
- a liner 5 i.e., the cast insert member
- the liner 5 is made from a steel.
- the core 6 is formed of a bimetallic alloy which includes Mn in an amount of 68% by weight, and accordingly it exhibits a thermal expansion coefficient remarkably larger than those of the liner 5 and the resulting cast product. Moreover, when cooled, the core 6 is designed so that it has an outside diameter slightly smaller than the inside diameter of the liner 5.
- the liner 5 and the core 6 were expanded by the heat of the molten aluminum alloy. Since the core 6 exhibited a thermal expansion coefficient remarkably larger than that of the liner 5, it contacted with the inner periphery of the liner 5 to press the liner 5 in the expanding direction. Thus, the clearance disappeared, and accordingly the molten aluminum alloy barely invaded between the liner 5 and the core 6. Moreover, the expanding stress arisen in the liner 5 was conveyed to press the molten aluminum alloy. In this pressed state, the molten aluminum alloy solidified. As a result, the casting defects resulting from the shrinkage cavities or the like could be inhibited from occurring.
- the liner 5 When the molten aluminum alloy started solidifying, the liner 5 was subjected to the shrinkage force arisen in the cast product. At this moment, however, the core 6 was still in the expanding state, and it still contacted with the inner peripheral surface of the liner 5. Consequently, the liner 5 was hardly deformed, and thereby it could be integrated with the cast product. When the casting mold was cooled, the core 6 shrunk greatly to produce a clearance between itself and the liner 5. Thus, the core 6 could be removed from the liner 5 with ease.
- the liner 5 could maintain the predetermined configuration, and it did not require the finish machining. Thus, it was possible to give the liner 5 an as-designed thickness. Accordingly, the liner 5 could exhibit its maximum mechanical strength.
- the casting mold of the Second Preferred Embodiment it is preferable to preliminarily heat the liner 5 and the core 6 to about 200 °C before charging the molten aluminum alloy into the casting mold. If the preliminary heating is done, the clearance between the liner 5 and the core 6 has disappeared before starting the charging of the molten aluminum alloy thereinto. Hence, it is possible to further reliably inhibit the invasion of the molten aluminum alloy into the clearance as well as the deformation of the liner 5 due to the pressure associated with the charging.
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Molds, Cores, And Manufacturing Methods Thereof (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Description
Claims (10)
- A method for producing a cast product with a concave portion, comprising the steps of:inserting a core (3; 6) projecting into a cavity (10) of a casting mold,charging a molten metal into the cavity (10), and solidifying the molten metal,the core (3; 6) exhibiting a thermal expansion coefficient being equivalent to or more than a thermal expansion coefficient exhibited by the molten metal,
whereina) the core temperature is sharply raised during casting and the core is thus expanded to apply a pressing force on the molten metal, andb) immediately after or before the solidification of the molten metal has been completed, the core (3; 6) is cooled by supplying water to a cooling water circuit provided in the casting mold in order to cool the core (3; 6) rapidly and forcibly before splitting the mold, whilec) increasing the temperature difference between the core (3) and the cast product. - Method according to claim 1, characterized in that said molten metal includes aluminium or an aluminium alloy.
- Method according to claim 1, characterized in that said molten metal includes zinc or a zinc alloy.
- Method according to one of the claims 1 to 3, characterized in that a cast insert member (5) is disposed around the outer periphery of said core (3; 6) and in that the core (3; 6) exhibits a thermal expansion coefficient being larger than the thermal expansion coefficient exhibited by the cast insert member (5).
- Method according to one of the claims 1 to 4, characterized in that said core (3; 6) is formed of a high-manganese-content alloy.
- Method according to claim 5, characterized in that said high-manganese-content alloy includes Mn in an amount of from 10 to 25 % by weight, C in an amount of from 0.2 to 1.5 & by weight, Cr in an amount of from 1 to 3 % by weight, and the balance of Fe and inevitable impurities.
- Method according to one of the claims 1 to 4, characterized in that said core (3; 6) is formed of an austenite stainless steel.
- Method according to one of the claims 1 to 4, characterized in that said core (3; 6) is formed of a bimetallic alloy.
- Method according to claim 8, characterized in that said bimetallic alloy includes Mn in an amount of from 65 to 80 % by weight, Cr in an amount of from 10 to 20 % by weight, and the balance of Ni and inevitable impurities.
- Method according to one of the claims 1 to 9, characterized in that said core (3; 6) is untapered where it is brought into contact with the molten metal.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP213128/93 | 1993-08-27 | ||
JP5213128A JPH0760399A (en) | 1993-08-27 | 1993-08-27 | Metal mold structure for casting |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0642855A1 EP0642855A1 (en) | 1995-03-15 |
EP0642855B1 true EP0642855B1 (en) | 1999-03-31 |
Family
ID=16634046
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP94113405A Expired - Lifetime EP0642855B1 (en) | 1993-08-27 | 1994-08-26 | Casting mold |
Country Status (4)
Country | Link |
---|---|
US (1) | US5615726A (en) |
EP (1) | EP0642855B1 (en) |
JP (1) | JPH0760399A (en) |
DE (1) | DE69417494T2 (en) |
Families Citing this family (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4414168A1 (en) * | 1994-04-22 | 1995-10-26 | Alcan Gmbh | Process for connecting two workpieces and composite component produced according to the process |
JP2002283003A (en) * | 2001-03-22 | 2002-10-02 | Toyota Industries Corp | Casting method and metallic mold apparatus for casting |
DE19904971A1 (en) * | 1999-02-06 | 2000-08-31 | Vaw Alucast Gmbh | Method and device for manufacturing engine blocks |
DE102005004481B3 (en) * | 2005-01-31 | 2006-06-14 | Hydro Aluminium Deutschland Gmbh | Cooling mold is dimensioned so that the heat expansion coefficient of the mold fits the heat expansion coefficient of the casting material to be cast made from nickel- and/or manganese-alloyed cast iron |
DE102005054616B3 (en) * | 2005-11-16 | 2006-11-09 | Hydro Aluminium Mandl&Berger Gmbh | Durable mold for light metal castings, especially cylinder heads, has a mold body with hollow zones to mold insert bodies to take the molten metal with shoulder in a positive fit at shaped holders and spaces to allow expansion of cold molds |
JP5670034B2 (en) * | 2009-04-27 | 2015-02-18 | 錦見鋳造株式会社 | Method for manufacturing thin-walled spheroidal graphite cast iron products |
JP5741407B2 (en) * | 2011-11-28 | 2015-07-01 | トヨタ自動車株式会社 | Casting method and casting mold |
JP6266326B2 (en) * | 2013-12-06 | 2018-01-24 | 株式会社ケーヒン | Casting die apparatus and casting method |
CN104084554A (en) * | 2014-08-04 | 2014-10-08 | 东莞台一盈拓科技股份有限公司 | Die-cast formation method of amorphous alloy product |
JP6747938B2 (en) * | 2016-07-12 | 2020-08-26 | リョービ株式会社 | Tilting gravity casting machine and tilting gravity casting method |
CN113927022A (en) * | 2021-10-15 | 2022-01-14 | 泰州市锦峰新材料科技有限公司 | Automatic demoulding equipment for casting high-temperature alloy bar |
CN114029454A (en) * | 2021-11-05 | 2022-02-11 | 西峡县众德汽车部件有限公司 | Casting method for solving shrinkage porosity of casting |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1396341A (en) * | 1920-07-27 | 1921-11-08 | Rautenbach Arthur | Casting and mold therefor |
FR1076338A (en) * | 1952-03-18 | 1954-10-26 | Carron Parlanti Ltd | Process for casting hollow objects in light metal or in light alloy, and device for implementing this process |
DE973984C (en) * | 1952-05-16 | 1960-08-11 | Gustav Lauterjung | Metallic core for casting molds, molds or the like. |
FR2108852A7 (en) * | 1970-10-13 | 1972-05-26 | Leroy Somer | Casting cylindrical workpieces - in a mould with a core having a slip surface |
JPS5925361A (en) * | 1982-07-30 | 1984-02-09 | Hiroyuki Nohira | Separation of amino acid and mandelic acid form compounded substance of amino acid and mandelic acid |
GB2193914B (en) * | 1986-08-19 | 1990-08-15 | Metal Castings | Casting |
JPH0750049Y2 (en) * | 1986-11-25 | 1995-11-15 | イズミ工業株式会社 | Strut for thermal expansion suppression piston |
JPS63144845A (en) * | 1986-12-09 | 1988-06-17 | Mitsubishi Heavy Ind Ltd | Production of hollow casting |
JPS63281760A (en) * | 1987-05-13 | 1988-11-18 | Honda Motor Co Ltd | Production of cylinder head for internal combustion engine |
JP2802384B2 (en) * | 1988-09-20 | 1998-09-24 | マツダ株式会社 | Core for casting |
ZA916407B (en) * | 1990-08-14 | 1992-04-29 | Reilly Royalties Ltd | Improvements to castings |
US5251683A (en) * | 1991-03-11 | 1993-10-12 | General Motors Corporation | Method of making a cylinder head or other article with cast in-situ ceramic tubes |
-
1993
- 1993-08-27 JP JP5213128A patent/JPH0760399A/en active Pending
-
1994
- 1994-08-26 DE DE69417494T patent/DE69417494T2/en not_active Expired - Fee Related
- 1994-08-26 EP EP94113405A patent/EP0642855B1/en not_active Expired - Lifetime
-
1995
- 1995-12-26 US US08/578,487 patent/US5615726A/en not_active Expired - Fee Related
Also Published As
Publication number | Publication date |
---|---|
DE69417494D1 (en) | 1999-05-06 |
DE69417494T2 (en) | 1999-07-22 |
JPH0760399A (en) | 1995-03-07 |
EP0642855A1 (en) | 1995-03-15 |
US5615726A (en) | 1997-04-01 |
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